Lens holder driving device capable of avoiding deleterious effect on hall elements

ABSTRACT

An AF unit of a lens holder driving device includes a lens holder, a focusing coil, a permanent magnet having a plurality of permanent magnet pieces having first surfaces opposed to the focusing coil, a magnet holder holding the permanent magnet, and first and second leaf springs supporting the lens holder in a direction of an optical axis shiftably. An image stabilizer portion includes a fixed portion disposed near the second leaf spring, a supporting member swingably supporting the AF unit with respect to the fixed portion, an image stabilizer coil having a plurality of image stabilizer coil portions disposed so as to oppose to second surfaces of the plurality of permanent magnet pieces that are perpendicular to the first surfaces, and a plurality of Hall elements. Each Hall element is disposed at a position where the image stabilizer coil portion is separated into a plurality of coil parts.

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2011-157035, filed on Jul. 15, 2011, thedisclosure of which is incorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION

This invention relates to a lens holder driving device and, inparticular, to a lens holder driving device capable of picking up astatic image without blurry images by stabilizing the blurry images(movement) occurring upon shooting the static image using a miniaturecamera for a mobile terminal.

Hitherto, various lens holder driving devices has been proposed whichare capable of taking photographs with a high degree by stabilizingblurry images on an image-forming surface although there are blurryimages (movement) upon shooting the static image.

As image stabilizing methods, “optical methods” such as a sensor shiftmethod or a lens shift method and “a software stabilizing method” forstabilizing the blurry images using image processing by software areknown. An image stabilizing method introduced in the mobile terminalmainly adopts the software stabilizing method.

The software stabilizing method is disclosed, for example, in JapaneseUnexamined Patent Application Publication No. H11-64905(JP-A-H11-064905) (which will be also called Patent Document 1). Thesoftware stabilizing method disclosed in Patent Document 1 comprises thesteps of removing noise components from detected results of detectionmeans, of calculating, from a detected signal in which the noisecomponents are removed, particular information necessary to stabilizeimage blurred due to an image blurring of an image pickup device,thereby making a picked-up image be at a standstill in a nonshakingstate where the image pickup device remains at rest.

However, the image stabilizing method of “the software stabilizingmethod” disclosed in the Patent Document 1 has a problem so that imagequality degrades in compassion with the “optical method” which willlater be described. In addition, the image stabilizing method of thesoftware stabilizing method has disadvantage so that a taking timeinterval becomes longer because processing of the software is includedtherein.

Therefore, as the image stabilizing methods, request of “the opticalmethods” are on the increase with higher pixels in recent years. As theimage stabilizing methods of “the optical methods”, “a sensor shiftmethod”, “a lens shift method”, and “an optical unit tilt method” areknown.

The sensor shift method is disclosed, for example, in JapaneseUnexamined Patent Application Publication No. 2002-274242(JP-A-2002-274242) (which will be also called Patent Document 2). Adigital camera disclosed in Patent Document 2 has structure in which animage pickup device (CCD) can shift with a center at a referenceposition (center) by an actuator. The CDD is disposed in a CCD movingportion. The CCD can move in a X-Y plane orthogonal to a Z-axis by theCCD moving portion. The CCD moving portion mainly comprises threemembers: a base plate fixed to a housing; a first slider moving withrespect to the base plate in a direction of an X-axis; and a secondslider moving with respect to the first slider in a direction of aY-axis.

However, in “the sensor shift method” as disclosed in Patent Document 2,the CCD moving portion (a movable mechanism) becomes large. It istherefore difficult in terms of size (outer dimensions, a height) toadopt the image stabilizer of the sensor shift method to a miniaturecamera for a mobile phone.

Now, the description will proceed to the lens shift method.

By way of illustration, Japanese Unexamined Patent ApplicationPublication No. 2009-145771 (JP-A-2009-145771) (which will be alsocalled Patent Document 3) discloses an image stabilizing deviceincluding an image stabilizing unit for driving a correction lens. Theimage stabilizing unit comprises a base plate serving as a fixed member,a movable mirror barrel holding the correction lens movably, three ballssandwiched between the base plate and the movable mirror barrel, and aplurality of elastic bodies for elastically supporting the movablemirror barrel with respect to the base plate, two coils fixed to thebase plate, and two magnets fixed to the movable mirror barrel.

In addition, Japanese Unexamined Patent Application Publication No.2006-65352 (JP-A-2006-065352) (which will be also called Patent Document4) discloses “an image stabilizing device” for stabilizing image blurredby moving and controlling a particular lens group (which will later becalled “a correction lens”) among an image pickup optical systemcomprising a plurality of lens groups in two directions orthogonallycrossing to each other within a plane perpendicular to an optical axis.In the image stabilizing device disclosed in Patent Document 4, thecorrection lens is movably supported with respect to a fixed frame upand down (in a pitch direction) and from side to side (in a yawdirection) via a pitching moving box and a yawing moving frame.

Japanese Unexamined Patent Application Publication No. 2008-26634(JP-A-2008-026634) (which will be also called Patent Document 5)discloses “an image stabilizing unit” including a stabilizing opticalmember for stabilizing blurry images formed by an imaging optical systemby being moved to a direction crossed with an optical axis of theimaging optical system. In the stabilizing optical member disclosed inPatent Document 5, a lens holding flame for holding a correction lens ismovably supported with respect to a receiving barrel in a pitchdirection and a yaw direction via a pitch slider and a yaw slider.

Japanese Unexamined Patent Application Publication No. 2006-215095(JP-A-2006-215095) (which will be also called Patent Document 6)discloses “an image stabilizing device” which is capable of moving acorrection lens by small driving force and which is capable of rapidlyand accurately stabilizing the blurry images. The image stabilizingdevice disclosed in Patent Document 5 comprises a holding frame holdingthe correction lens, a first slider for slidably supporting the holdingframe in a first direction (a pitch direction), a second slider forslidably supporting the holding frame in a second direction (a yawdirection), a first coil motor for driving the first slider in the firstdirection, and a second coil motor for driving the second slider in thesecond direction.

Japanese Unexamined Patent Application Publication No. 2008-15159(JP-A-2008-015159) (which will be also called Patent Document 7)discloses a lens barrel comprising an image stabilizing optical systemprovided to enable to move in a direction orthogonal to an optical axis.In the image stabilizing optical system disclosed in Patent Document 7,a movable VR unit disposed in a VR body unit holds a correction lens (athird lens group) and is disposed so as to enable to move in a X-Y planeorthogonal to the optical axis.

Japanese Unexamined Patent Application Publication No. 2007-212876(JP-A-2007-212876) (which will be also called Patent Document 8 andwhich corresponds to U.S. Pat. No. 7,619,838) discloses “an imagestabilizer” which is capable to stabilize image blurred by performingcontrol so that the optical axis of a correction lens held in a movingframe may be aligned with the optical axis of a lens system by movingthe correction lens in first and second directions orthogonal to theoptical axis of the lens system by driving means.

Japanese Unexamined Patent Application Publication No. 2007-17957(JP-A-2007-017957) (which will be also called Patent Document 9)discloses “an image stabilizer” for stabilizing image blurred by drivinga correcting lens for stabilizing the blurry images that are formed by alens system by operation of a lens driving part in a first direction anda second direction which are perpendicular to an optical axis of thelens system and which are perpendicular to each other. In the imagestabilizer disclosed in Patent Document 9, the lens driving part isprovided at one side of the correcting lens in the directionperpendicular to the optical axis.

Japanese Unexamined Patent Application Publication No. 2007-17874(JP-A-2007-017874) (which will be also called Patent Document 10 andwhich corresponds to U.S. Pat. No. 7,650,065) discloses “an imagestabilizer” which is capable to stabilize blurry images by performingcontrol so that the optical axis of a correction lens held in a movingframe may be aligned with the optical axis of a lens system by movingthe correction lens in first and second directions which areperpendicular to the optical axis of the lens system and which areperpendicular to each other. The image stabilizer disclosed in PatentDocument 10 comprises driving means including a coil and a magnet whichcan be relatively moved. One of the coil and the magnet is fixed to amoving frame while another is fixed to a supporting frame for supportinga movable frame movably. In addition, the image stabilizer disclosed inPatent Document 10 comprises a first Hall element for detecting positioninformation related to the first direction of the correction lens bydetecting a magnetic force of the magnet and a second Hall element fordetecting position information related to the second direction of thecorrection lens by detecting the magnetic force of the magnet.

Any of the image stabilizers (the image stabilizing devices) of “thelens shift method” disclosed in the above-mentioned Patent Documents 3to 10 has structure for moving and adjusting the correction lens in aplane perpendicular to the optical axis. However, such image stabilizers(the image stabilizing devices) have problems in which structure iscomplicated and they are unsuited for miniaturization. That is, like inthe above-mentioned image stabilizer of the sensor shift method, it isdifficult in terms of size (outer dimensions, a height) to adopt theimage stabilizer of the lens shift method to the miniature camera forthe mobile phone.

In order to resolve the above-mentioned problems, an image stabilizer(an image stabilizing device) has been proposed which stabilizes blurryimages (image blurred) by swinging a lens module (a camera module) forholding a lens and a pickup device (an image sensor) in itself. Such amethod will be referred to herein as “an optical unit tilting method”.

Now, the description will proceed to “the optical unit tilting method”.

By way of illustration, Japanese Unexamined Patent ApplicationPublication No. 2007-41455 (JP-A-2007-041455) (which will be also calledPatent Document 11) discloses “an image stabilizer of an optical device”comprising a lens module for holding a lens and an imaging element, aframe structure for rotatably supporting the lens module by rotaryshafts, driving means (actuators) for rotating the lens module withrespect to the frame structure by imparting driving force to drivenparts (rotors) of the rotary shafts, and energizing means (leaf springs)for energizing the driving means (the actuators) to the driven parts(the rotors) of the rotary shafts. The frame structure comprises aninner frame and an outer frame. The driving means (the actuators) isdisposed so as to be in contact with the driven parts (the rotors) ofthe rotary shafts from directions perpendicular to an optical axis. Thedriving means (the actuators) comprises a piezoelectric element and anaction part of the rotary shafts side. The action part drives the rotaryshafts by vertical vibrations and bending vibrations of thepiezoelectric element.

However, it is necessary for the image stabilizer of “the optical unittilting method” disclosed in Patent Document 11 to cover the lens modulewith the frame structure comprising the inner frame and the outer frame.As a result, there is a problem in which the image stabilizer becomeslarge.

In addition, Japanese Unexamined Patent Application Publication No.2007-93953 (JP-A-2007-093953) (which will be also called Patent Document12) discloses “an image stabilizer for a camera” for stabilizing blurryimages upon shooting a static image by accommodating a camera module inwhich a pickup lens and an image sensor are integrated in a housing, byswingably mounting the camera module in housing at a center of first andsecond axes which are orthogonal to a pickup optical axis and whichcross each other at right angles, and by controlling the attitude of thecamera module as a whole in the housing in response to a shake of thehousing detected by a shake sensor. The image stabilizer for the cameradisclosed in Patent Document 12 comprises an intermediate frame forswingably supporting an inner frame in which the camera module is fixedat the first axis as a center from the outside thereof, an outer frame,fixed to the housing, for swingably supporting the intermediate frame atthe second axis as a center from the outside thereof, first drivingmeans, mounted inside the intermediate frame, for swinging the innerframe around the first axis in response to a shake signal from a shakesensor (a first sensor module for detecting a shake in a pitchdirection), and second driving means, mounted inside the outer frame,for swinging the intermediate frame around the second axis in responseto a shake signal from a shake sensor (a second sensor module fordetecting a shake in a yaw direction). The first driving means comprisesa first stepping motor, a first reduction gear train for reducing arotation thereof, and a first cam for swinging the inner frame through afirst cam follower provided to the inner frame by rotating it integralwith a final stage gear. The second driving means comprises a secondstepping motor, a second reduction gear train for reducing a rotationthereof, and a second cam for swinging the intermediate frame through asecond cam follower provided to the intermediate frame by rotating itintegral with a final stage gear.

However, also in the image stabilizer of “the optical unit tiltingmethod” disclosed in Patent Document 12, it is necessary to cover thecamera module with the inner frame, the intermediate frame, and theouter frame. As a result, the image stabilizer becomes large.Furthermore, inasmuch as there are the rotary axes in “the optical unittilting method”, there is a problem in which friction is producedbetween a hole and an axis and it results in exhibiting hysteresis.

Furthermore, Japanese Unexamined Patent Application Publication No.2009-288770 (JP-A-2009-288770) (which will be also called PatentDocument 13 and which corresponds to US 2011/097062) discloses anoptical photography device which is capable of reliably stabilizingblurry images by improving the structure of an photography unit drivemechanism for stabilizing the blurry images in an photography unit. Theoptical photography device disclosed in Patent Document 13 comprises,inside a fixed cover, the photography unit (a movable module) and animage stabilizing mechanism for stabilizing blurry images by displacingthe photography unit. The photography unit is for moving a lens along adirection of an optical axis. The photography unit comprises a movingbody for holding the lens and a fixed aperture therein, a lens drivingmechanism for moving the moving body in the direction of the opticalaxis, and a supporting body in which the lens driving mechanism and themoving body are mounted. The lens driving mechanism comprises a lensdriving coil, a lens driving magnet, and a yoke. The photography unit issupported to a fixed body via four suspension wires. At two positions onboth sides sandwiching the optical axis, a first photography unit drivemechanism and a second photography unit drive mechanism, which are forstabilizing the blurry images, are respectively provided as a pair. Ineach of their photography unit drive mechanisms, a photography unitdrive magnet is held in a movable body side while a photography unitdrive coil is held in a fixe body side.

However, in the optical photography device of ““the optical unit tiltingmethod” disclosed in Patent Document 13, it is necessary to use thephotography unit drive magnets as well as the lens drive magnet. As aresult, there is a problem in which the optical photography devicebecomes large.

In addition, Japanese Unexamined Patent Application Publication No.2011-107470 (JP-A-2011-107470) (which will be also called PatentDocument 14) discloses a lens driving device which is capable of notonly driving a lens in a direction of an optical axis but alsostabilizing blurry images. The lens driving device disclosed in PatentDocument 14 comprises a first holding body for holding the lens so as tobe movable it in the direction of the optical axis (Z direction), asecond holding body for holding the first holding body so as to bemovable it in the Z direction, a fixed body for holding the secondholding body so as to be movable it in a direction which issubstantially orthogonal to the Z direction, a first driving mechanismfor driving the first holding body in the Z direction, a second drivingmechanism for driving the second holding body in an X direction, and athird driving mechanism for driving the second holding body in a Ydirection. The first holding body is supported to the second holdingbody by a first supporting member made of an elastic material so as tobe movable in the Z direction. The second holding body is supported tothe fixed body by a second supporting member made of an elastic materialso as to be movable in the Z direction. The first driving mechanismcomprises a first drive coil and a first drive magnet, the seconddriving mechanism comprises a second drive coil and a second drivemagnet, and the third driving mechanism comprises a third drive coil anda third drive magnet.

In the lens driving device disclosed in Patent Document 14, three kindsof driving mechanisms consisting of the first through the third drivingmechanism require as driving mechanisms, and each of the first throughthird driving mechanisms comprises a coil and a magnet, independently.Therefore, there is a problem in which the number of parts is increased.

Japanese Unexamined Patent Application Publication No. 2011-113009(JP-A-2011-113009) (which will be also called Patent Document 15)discloses a lens driving device which uses a plurality of wires as thesecond supporting member and which comprises a buckling preventionmember for preventing buckling of the wires while its basic structure issimilar to the lens driving mechanism disclosed in the above-mentionedPatent Document 14. Each wire is formed in a straight line and thesecond holding member is supported by the wires so as to be movable inthe direction which is substantially orthogonal to the Z direction. Thebuckling prevention member is made of an elastic member and becomeselastically deformed in the Z direction at a force smaller than abuckling load of the wire. More specifically, the buckling preventionmember comprises a wire fixed portion formed to a leaf spring for thefirst supporting member. When a force applies to a movable part such asthe second holding body downwards, the wire fixed portion becomeselastically deformed downwards.

In also the lens driving device disclosed in Patent Document 15, in themanner similar to the lens driving device disclosed in Patent Document14, there is a problem in which the number of parts is increased. Inaddition, the lens driving device disclosed in Patent Document 15 merelyprevents the wires from buckling because the force applies to the wiresin a direction to compress. In other words, the lens driving devicedisclosed in Patent Document 15 does not take into account in a casewhere the wires may rupture because a force applies to the wires in adirection to extend.

Therefore, the present inventor and another proposed an image stabilizerwhich is capable of miniaturizing and lowering a height by sharing apermanent magnet for an auto-focusing (AF) lens driving device as apermanent magnet for the image stabilizer (see, Japanese UnexaminedPatent Application Publication No. 2011-65140 (JP-A-2011-065140) (whichwill be also called Patent Document 16)).

The image stabilizer disclosed in Patent Document 16 is called an imagestabilizer of “a barrel shift method” because camera shake is correctedby moving a lens barrel received in an AF lens driving device in itself.In addition, the image stabilizers of “the barrel shift method” areclassified into “a moving magnet method” in which the permanent magnetmoves (is movable) and “a moving coil method” in which the coil moves(is movable).

Patent Document 16 discloses, as the image stabilizer of “the movingmagnet method” in a second exemplary embodiment thereof”, an imagestabilizer which is provided with a permanent magnet comprising fourfirst permanent magnet pieces and four second permanent magnet pieceswhich are disposed so as to apart from up and down in a direction of anoptical axis and which is provided with a stabilizer coil disposedbetween the upper four first permanent magnet pieces and the lower foursecond permanent magnet pieces. That is, the second exemplary embodimentcomprises the image stabilizer of “the moving magnet method” includingthe permanent magnet comprising eight permanent magnet pieces in total.

In the image stabilizer disclosed in Patent Document 16, a base isdisposed so as to apart from at a bottom portion of the auto-focusinglens driving device and a plurality of suspension wires have one endswhich are fixed to the base at outer regions thereof. The plurality ofsuspension wires has other ends which are firmly fixed to theauto-focusing lens driving device.

In the image stabilizer disclosed in Patent Document 16, there is aproblem in which the number of parts is increased because the permanentmagnet comprises the eight permanent magnet pieces. In addition, thereis another problem in which it expends in time on assembling because theimage stabilizer coil is disposed between the upper four first permanentmagnet pieces and the lower four second permanent magnet pieces.

Japanese Unexamined Patent Application Publication No. 2011-85666(JP-A-2011-085666) (which will be also called Patent Document 17) alsodiscloses a lens driving device which shares an AF control magnet as animage stabilizer control magnet. The lens driving device disclosed inPatent Document 17 comprises a lens holder including a first coil (an AFcoil) disposed at an outer periphery of a lens, a magnet holderconfigured to fix a magnet having a first surface facing the first coil,springs for supporting the lens holder so as to couple the lens holderwith the magnet holder and also so that the lens holder is moved withrespect to the magnet in a direction of an optical axis, and a basemember configured so that a second coil (an image stabilizer coil) isfixed to face a second surface of the magnet that is perpendicular tothe first surface thereof. A lens holding unit, which comprises the lensholder, the magnet, the magnet holder, and the springs, is held so as tobe relatively movable in a direction perpendicular to the optical axisrelative to the base member.

Patent Document 17 discloses the lens driving device as a six exemplaryembodiment in which a position detection sensor is disposed at aclearance of the image stabilizer coil wound. A Hall element is used asthe position detection sensor. In addition, the lens holding unit isheld by suspension wires which are disposed to a fixed portion at fourcorners thereof. That is, the suspension wires have one ends fixed tothe four corners of the fixed portion and other ends which are firmlyfixed to the lens holding unit.

In the lens driving device disclosed in Patent Document 17, the positiondetection sensor is disposed at the image stabilizer coil (the secondcoil). And, in the manner which is described above, the Hall element isused as the position detection sensor. When the Hall element is disposedat the clearance (i.e. inside a loop portion) of the image stabilizercoil (the second coil), there is a problem in which the Hall element issubjected to an adverse effect due to a magnetic field occurring by anelectric current flowing in the image stabilizer coil (the second coil).That is, in the manner which will later be described in more detail inconjunction with FIGS. 5 through 10, inversed phase occurs in a band notlower than a primary resonance frequency of the lens driving device(actuator) because moving of the magnet shifts 180 degrees in phase incompassion with a phase of the electric current flowing in the secondcoil (the image stabilizer coil). As a result, there is a problem inwhich resonance occurs in an output of the Hall element.

SUMMARY OF THE INVENTION

It is therefore an exemplary object of the present invention to providea lens holder driving device which is capable of keeping a Hall elementserving as a position detection sensor away from subjecting adverseeffect due to a magnetic field occurring by an electric current flowingin a coil.

Other objects of this invention will become clear as the descriptionproceeds.

On describing the gist of an exemplary aspect of this invention, it ispossible to be understood that a lens holder driving device comprises anauto-focusing lens holder driving portion moving a lens holder holding alens barrel along an optical axis, and an image stabilizer portionstabilizing image blurred by moving said auto-focusing lens holderdriving portion in first and second directions which are orthogonal tothe optical axis and which are perpendicular to each other. According tothe exemplary aspect of this invention, the auto-focusing lens holderdriving portion comprises a focusing coil fixed to the lens holder, apermanent magnet comprising a plurality of permanent magnet pieces whichhave first surfaces opposed to the focusing coil and which are disposedoutsides of the focusing coil with respect to the optical axis in aradial direction so as to oppose to each other in the first directionand the second direction, a magnet holder, disposed around the peripheryof the lens holder, holding said permanent magnet and having first andsecond ends opposite to each other in a direction of the optical axis,and first and second leaf springs, mounted to the first and the secondends of the magnet holder, supporting the lens holder in the directionof the optical direction shiftably so as to position the lens holder inthe radial direction. The image stabilizer portion comprises a fixedportion disposed apart from the auto-focusing lens holder drivingportion in the direction of the optical axis at a position in thevicinity of the second leaf spring, a supporting member swingablysupporting the auto-focusing lens holder driving portion in the firstdirection and the second direction with respect to the fixed portion, animage stabilizer coil comprising a plurality of image stabilizer coilportions mounted on the fixed portion so as to oppose to second surfacesof the plurality of plurality of permanent magnet pieces that areperpendicular of to the first surfaces, the image stabilizer coilcomprising specific image stabilizer coil portions, among the pluralityof hand blurring correction coil portions, disposed in the firstdirection and the second direction, each of the specific imagestabilizer coil portions being divided into a plurality of coil parts soas to separate in a longitudinal direction of the permanent magnet pieceopposed thereto, and a plurality of Hall elements disposed on the fixedportion at positions where each of the specific image stabilizer coilportions are separated into the plurality of coil portions.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an external perspective view of a lens holder driving deviceaccording to a first exemplary embodiment of the present invention;

FIG. 2 is a partial vertical cross sectional view of the lens holderdriving device illustrated in FIG. 1;

FIG. 3 is an exploded perspective view of the lens holder driving deviceillustrated in FIG. 1;

FIG. 4 is a perspective view of a coil board and an image stabilizercoil formed therein which are used in the lens holder driving deviceillustrated in FIG. 1;

FIG. 5 is a perspective view showing a relationship between a relatedmagnetic circuit and Hall elements;

FIG. 6 is a vertical cross sectional view showing a relationship betweenthe related magnetic circuit and the Hall elements;

FIG. 7 is a vertical cross sectional view shoring a relationship betweenthe related magnetic circuit and the Hall elements in a case ofdisplacing an AF unit in a fore-and-aft direction X;

FIG. 8 is a view showing a frequency response of a front-side Hallelement in the related magnetic circuit;

FIGS. 9A, 9B, and 9C are views showing relationships between phases andmagnitudes among a magnetic flux density a of a magnetic field Bgenerated by the a front-side permanent magnetic piece, a magnetic fluxdensity b of a magnetic field B₁₁ generated by a first IS currentI_(IS1) flowing through a front-side image stabilizer coil, and a totalmagnetic flux density (a+b) detected by the front-side Hall element in aregion I, a region II, and a region III of FIG. 8, respectively;

FIG. 10 is a view tabulated for the relationships of FIGS. 9A-9C;

FIG. 11 is a perspective view showing a relationship between a magneticcircuit and Hall elements for use in the lens holder driving deviceillustrated in FIG. 1;

FIG. 12 is a vertical cross sectional view showing a relationshipbetween the magnetic circuit and the Hall elements illustrated in FIG.11;

FIG. 13 is a vertical cross sectional view showing a relationshipbetween the magnetic circuit and the Hall elements illustrated in FIG.11 in a case of displacing an AF unit in a fore-and-aft direction X;

FIG. 14 is a cross sectional view taken on line XIV-XIV of FIG. 13;

FIG. 15 is a view showing a frequency response of a front-side Hallelement in the magnetic circuit illustrated in FIG. 11;

FIGS. 16A, 16B, and 16C are views showing relationships between phasesand magnitudes among a magnetic flux density a of a magnetic field Bgenerated by the a front-side permanent magnetic piece, a magnetic fluxdensity b of a magnetic field B₁₁ generated by a first IS current IIS1flowing in a front-side image stabilizer coil, and a total magnetic fluxdensity (a+b) detected by the front-side Hall element in a region I, aregion II, and a region III of FIG. 15, respectively;

FIG. 17 is a view tabulated for the relationships of FIGS. 16A-16C;

FIG. 18 is a cross sectional view showing a relationship of a placementamong one permanent magnet piece of the permanent magnet, a focusingcoil disposed around it, and an image stabilizer coil portion in themagnetic circuit illustrated in FIG. 11;

FIG. 19 is a partial perspective view enlargedly showing a part fixing asecond end portion of a suspension wire to an upper leaf spring for usein the lens holder driving device illustrated in FIG. 1;

FIG. 20 is a partial cross sectional view of the fixed part illustratedin FIG. 19;

FIG. 21 is a perspective view showing a assembly of a coil board and aflexible printed circuit (FPC) for use in the lens holder driving deviceillustrated in FIG. 1 seen from a rear side;

FIG. 22 is a plan view showing a state where a shielding cover isomitted from the lens holder driving device illustrated in FIG. 1;

FIG. 23 is a partial enlarged perspective view enlargedly showing atied-up part of an end portion of a wire composed of the focusing coilin FIG. 22;

FIG. 24 is a vertical cross sectional view of a lens holder drivingdevice according to a second exemplary embodiment of the presentinvention; and

FIG. 25 is an exploded perspective view of the lens holder drivingdevice illustrated in FIG. 24.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to Figures, the description will proceed to exemplaryembodiments of the present invention.

Referring to FIGS. 1 through 3, the description will proceed to a lensholder driving device 10 according to a first exemplary embodiment ofthis invention. FIG. 1 is an external perspective view of the lensholder driving device 10. FIG. 2 is a partial vertical cross sectionalview of the lens holder driving device 10. FIG. 3 is an explodedperspective view of the lens holder driving device 10.

Herein, in the manner shown in FIGS. 1 through 3, an orthogonalcoordinate system (X, Y, Z) is used. In a state illustrated in FIGS. 1through 3, in the orthogonal coordinate system (X, Y, X), an X-axisdirection is a fore-and-aft direction (a depth direction), a Y-axisdirection is a left-and-right direction (a width direction), and aZ-axis direction is an up-and-down direction (a height direction). Inaddition, in the example being illustrated in FIGS. 1 through 3, theup-and-down direction Z is a direction of an optical axis O of a lens.In the first exemplary embodiment, the X-axis direction (thefore-and-aft direction) is called a first direction while the Y-axisdirection (the left-and-right direction) is called in a seconddirection.

However, in an actual use situation, the direction of the optical axisO, namely, the Z-axis direction becomes a fore-and-aft direction. Inother words, an upper direction of the Z-axis becomes a front directionwhile a lower direction of the Z-axis becomes a rear direction.

The illustrated lens driving device 10 is mounted to a mobile terminalsuch as a camera-equipped cellular mobile phone which is enable toautomatic focusing, a smart phone, a notebook personal computer, atablet-type personal computer, a mobile-type game machine, a Web camera,a vehicle-mounted camera, or the like. The lens holder driving device 10comprises an auto-focusing lens holder driving portion 20 which willlater be described, and an image stabilizer portion (which will later bedescribed) for stabilizing blurry images (vibrations) occurring in theauto-focusing lens holder driving portion 20 upon shooting a staticimage using a miniature camera for the mobile terminal and is a devicewhich is capable of picking up the image without image blurred. Theimage stabilizer portion of the lens holder driving device 10 stabilizesthe blurry images by moving the auto-focusing lens holder drivingportion 20 in the first direction (the fore-and-aft direction) X and thesecond direction (the left-and-right direction) Y which are orthogonalto the optical axis O and which are perpendicular to each other.

The auto-focusing lens holder driving portion 20 is for moving the lensholder 14 (which will later be described) capable of mounting a lensbarrel (not shown) along the optical axis O. Apart from a bottom portionof the auto-focusing lens holder driving portion 20, a fixed portion 13is disposed. Although illustration is not made, the fixed portion 13 hasa lower portion (a rear portion) on which an image pickup devicedisposed on an image pickup board is mounted. The image pickup devicepicks up a subject image formed by the lens barrel to convert it into anelectric signal. The image pickup device may, for example, comprise aCCD (charge coupled device) type image sensor, a CMOS (complementarymetal oxide semiconductor) type image sensor, or the like. Accordingly,a camera module comprises a combination of the auto-focusing lens holderdriving portion 20, the image pickup board, and the image pickup device.

The fixed portion 13 comprises a base 14, a coil board 40, a flexibleprinted circuit (FPC) 44.

The base 14 has a ring-shaped which has the outside shape of arectangular and which has a circular opening 14 a in the interiorthereof.

The image stabilizer portion of the lens holder driving device 10comprises four suspension wires 16 having first end portions 161 fixedto four corner portions of the fixed portion 13, and an image stabilizercoil 18 disposed to face a permanent magnet 28 of the auto-focusing lensholder driving portion 20 (which will later be described) in the mannerwhich will later be described.

The four suspension wires 16 extend along the optical axis O andswingably support the auto-focusing lens holder driving portion 20 as awhole in the first direction (the fore-and-aft direction) X and thesecond direction (the left-and-right direction) Y. The four suspensionwires 16 have second end portions 162 which are fixed to an upper endportion of the above-mentioned auto-focusing lens holder driving portion20 in the manner which will later be described.

In the manner described above, the four suspension wires 16 serves as asupporting member for swingably supporting the auto-focusing lens holderdriving portion 20 with respect to the fixed portion 13 in the firstdirection Y and the second direction Y.

The image stabilizer portion of the lens holder driving device 10comprises a coil board 40 having a rectangular ring shape that isdisposed apart from to face the permanent magnet 28. The coil board 40is mounted on the base with the flexible printed circuit (FPC) 44 whichwill later be described is sandwiched therebetween. The above-mentionedimage stabilizer coil 18 is formed on the coil board 40.

In the manner which is described above, the fixed portion 13 comprises acombination of the base 14, the coil board 40, and the flexible printedcircuit (FPC) 44.

Referring now to FIG. 3, the description will proceed to theauto-focusing lens holder driving portion 20. The auto-focusing lensholder driving portion 20 is also called an AF unit.

The auto-focusing lens holder driving portion 20 comprises the lensholder 24 including a tubular portion 240 for holding the lens barrel, aring-shaped focusing coil 26 fixed to the lens holder 24 so as toposition around the tubular portion 240 thereof, a magnet holder 30 forholding the permanent magnet 28 disposed opposite to the focusing coil26 at the outside of the focusing coil 26, and first and second leafsprings 32 and 34 mounted on first and second ends 30 a and 30 b of themagnetic holder 30 in the direction of the optical axis O.

The first and second springs 32 and 34 support the lens holder 24 in thedirection of the optical axis O shiftably so as to position the lensholder 24 in a radial direction. In the example being illustrated, thefirst leaf spring 32 is called an upper leaf spring while the secondleaf spring 34 is called a lower leaf spring.

In addition, in the manner which is described above, in the actual usesituation, the upper direction in the Z-axis direction (the direction ofthe optical axis O) becomes the front direction while the lowerdirection in the Z-axis direction (the direction of the optical axis O)becomes the rear direction. Accordingly, the upper leaf spring 32 isalso called a front-side spring while the lower leaf spring 34 is alsocalled a rear-side spring.

The magnet holder 30 has configuration of a substantially octagonaltube. Specifically, the magnet holder 30 comprises an outer tubularportion 302 having an octagonal tubular shape, an octagonal upperring-shaped end portion 304 provided at an upper end (a front end, thefirst end) 30 a of the outer tubular portion 302, and an octagonal lowerring-shaped end portion 306 provided at a lower end (a rear end, thesecond end) 30 b of the outer tubular portion 302. The upper ring-shapedend portion 304 has eight upper protrusions 304 a which project at fourcorners upwards by two per corner. The lower ring-shaped end portion 306has four lower protrusions 306 a which project at four cornersdownwards.

The focusing coil 26 has an octagonal cylindrical shape which coincideswith an outer shape of the magnet holder 30 having the octagonal tubularshape. The permanent magnet 28 comprises four rectangular permanentmagnet pieces 282 which are disposed in the outer tubular portion 302having the octagonal tubular shape in the magnet holder 30 so as toapart from each other in the first direction (the fore-and-aftdirection) X and the second direction (the left-and-right direction) Y.The four permanent magnet pieces 282 are disposed with spaces betweenthem and the focusing coil 26. In the example being illustrated, eachpermanent magnet piece 282 has an inner end side polarised (magnetized)to the north pole and an outer end side polarised (magnetized) to thesouth pole.

The upper leaf spring (the front-side spring) 32 is disposed at an upperside (a front side) of the lens holder 24 in the direction of theoptical axis O while the lower leaf spring (the rear-side spring) 34 isdisposed at a lower side (a rear side) of the lens holder 24 in thedirection of the optical axis O.

The upper leaf spring (the front-side spring) 32 comprises an upperinner end portion 322 mounted on an upper end portion of the lens holder24 in the manner which will later be described and an upper outer endportion 324 mounted on the upper ring-shaped end portion 304 of themagnet holder 30 in the manner which will later be described. Betweenthe upper inner end portion 322 and the upper outer end portion 324, aplurality of upper arm portions 326 are provided. That is, the pluralityof upper arm portions 326 connects the upper inner end portion 322 tothe upper outer end portion 324.

The tubular portion 240 of the lens holder 24 has, at an upper endthereof, four upper protrusions 240 a projecting at four cornersupwards. The upper inner end portion 322 has four upper holes 322 a inwhich the four upper protrusions 240 a are compression inserted(charged), respectively. That is, the four upper protrusions 240 a ofthe tubular portion 240 of the lens holder 243 are compression inserted(charged) in the four upper holes 322 a of the upper inner end portion322 of the upper leaf spring 32, respectively.

On the other hand, the upper outer end portion 324 has eight upper holes324 a in which the eight upper protrusions 34 a of the magnet holder 30are charged, respectively. That is, the eight upper protrusions 34 a ofthe magnet holder 30 are charged in the eight upper holes 324 a of theupper outer end portion 324.

The upper leaf spring (the front-side spring) 32 further comprises fourarc-shaped extending portions 328 which extend at four corers of theupper outer end portion 324 in the radial direction outwards. The fourarc-shaped extending portions 328 have four wire fixing holes 328 a inwhich the second end portions 162 of the four suspension wires 16 areinserted (charged), respectively. A detailed structure of eacharc-shaped extending portion 328 will later be described with referenceto FIG. 19 in detail.

The lower leaf spring (the rear-side spring) 34 comprises a lower innerend portion 342 mounted on a lower end portion of the lens holder 24 inthe manner which will later be described and a lower outer end portion344 mounted on the lower ring-shaped end portion 306 of the magnetholder 30 in the manner which will later be described. Between the lowerinner end portion 342 and the lower outer end portion 344, a pluralityof lower arm portions 346 are provided. That is, the plurality of lowerarm portions 346 connects the lower inner end portion 342 to the lowerouter end portion 344.

The lower leaf spring 34 has a lower portion in which a spacer 36 havinga substantially same outside shape is disposed. More specifically, thespacer 36 comprises an outer ring portion 364 having a shape which issubstantially equivalent to that of the lower outer end portion 344 ofthe lower leaf spring 34 and an inner ring portion 364 having a shape soas to cover the lower inner end portion 342 and the lower arm portions346 of the lower leaf spring.

The tubular portion 240 of the lens holder 24 has, at a lower end, fourlower protrusions (not shown) projecting at four corners downwards. Thelower inner end portion 342 has four lower holes 342 a in which the fourlower protrusions are compression inserted (charged), respectively. Thatis, the four lower protrusions of the tubular portion 240 of the lensholder 24 are compression inserted (charged) in the four lower holes 342a of the lower inner end portion 342 of the lower leaf spring 34.

On the other hand, the lower outer end portion 344 of the lower leafspring 34 has four lower holes 344 a in which the four lower protrusions306 a of the magnet holder 30 are charged, respectively. The outer ringportion 364 of the spacer 36 also has four lower holes 364 a in whichthe four lower protrusions 306 a of the magnet holder 30 are compressioninserted at positions corresponding to the four lower holes 344 a,respectively. That is, the four lower protrusions 306 a of the magnetholder 30 are compression inserted in the four lower holes 364 a of theouter ring portion 364 of the spacer 36 via the four lower holes 344 aof the lower outer end portion 344 of the lower leaf spring 34,respectively.

An elastic member comprising the upper leaf spring 32 and the lower leafspring 34 serves as a guiding arrangement for guiding the lens holder 24so as to be movable in the direction of the optical axis O alone. Eachof the upper leaf spring 32 and the lower leaf spring 34 is made ofberyllium copper, phosphor bronze, or the like.

The tubular portion 240 of the lens holder 24 has an inner wall in whicha female screw thread (not shown) is cut. On the other hand, althoughthe illustration is not made, the lens barrel has an outer wall in whicha male screw thread screwed in the above-mentioned female screw threadis cut. In a case of fitting the lens barrel to the lens holder 24, itincludes the steps of rotating the lens barrel with respect to thetubular portion 240 of the lens holder 24 around the optical axis O toscrew it along the direction of the optical axis O thereby accommodatingthe lens barrel in the lens holder 24, and of connecting them to eachother via an adhesive agent or the like.

In the manner which will later be described, by flowing an auto-focusing(AF) current through the focusing coil 26, it is possible topositionally adjust the lens holder 24 (the lens barrel) in thedirection of the optical axis O according to interaction between amagnetic field of the permanent magnet 28 and a magnetic field due tothe AF current flowing through the focusing coil 26.

In the manner which is described above, the auto-focusing lens holderdriving portion (the AF unit) 20 comprises the lens holder 24, thefocusing coil 26, the permanent magnet 28, the magnet holder 30, theupper leaf spring 32, the lower leaf spring 34, and the spacer 36.

Referring now to FIG. 3, the description will proceed to the imagestabilizer portion of the lens holder driving device 10 in more detail.

In the manner which is described above, the image stabilizer portion ofthe lens holder driving device 10 comprises the four suspension wires 16having the first end portion 161 fixed to the fixed portion 13 at thefour corner portions thereof, and the image stabilizer coil 18 disposedto face the permanent magnet 28 of the above-mentioned auto-focusinglens holder driving portion 20.

The four suspension wires 16 extend along the optical axis O andswingably support the auto-focusing lens holder driving portion 20 as awhole in the first direction (the fore-and-aft direction) X and thesecond direction (the left-and-right direction) Y. The four suspensionwires 16 have the second end portions 162 which are fixed to the upperend portion of the above-mentioned auto-focusing lens holder drivingportion 20.

More specifically, in the manner which is described above, the fourarc-shaped extending portions 328 of the upper leaf spring 32 have thefour wire fixing holes 328 a in which the second end portions 162 of thefour suspension wires 16 are inserted (charged), respectively (see, FIG.3). In the four wire fixing holes 328 a, the second end portions 162 ofthe four suspension wires 16 are inserted (charged) and are fixed bymeans of an adhesive agent, solder, or the like.

Although each arc-shaped extending portion 328 has an L-shape in theexample being illustrated, of course, it is not limited to this.

Two of the four suspension wires 16 are also used to feed to thefocusing coil 26.

In the manner which is described above, the permanent magnet 28comprises the four permanent magnet pieces 282 which are disposed so asto oppose to each other in the first direction (the fore-and-aftdirection) X and the second direction (the left-and-right direction) Y.

The image stabilizer portion of the lens holder driving device 10comprises the ring-shaped coil board 40 which is inserted between thefour permanent magnet pieces 282 and the base 14 and which is disposedso as to apart from them. The coil board 40 has, at four cornersthereof, four through holes 40 a through which the four suspension wires16 pass and in which the first end portions 161 are fixed. Theabove-mentioned image stabilizer coil 18 is formed on the coil board 40.

Herein, in the four permanent magnet pieces 282, the permanent magnetpieces disposed with respect to the optical axis O at a front side, arear side, a left side, and a right side are called a front-sidepermanent magnet piece 282 f, a rear-side permanent magnet piece 282 r,a left-side permanent magnet piece 282 l, and a right-side permanentmagnet piece 282 r, respectively.

Referring to FIG. 4 also, on the coil board 40, four image stabilizercoil portions 18 f, 18 b, 18 l, and 18 r are formed as the imagestabilizer coil 18.

Disposed opposite to each other in the first direction (the fore-and-aftdirection) X, the two image stabilizer coil portions 18 f and 18 b arefor moving (swinging) the auto-focusing lens holder driving portion (theAF unit) 20 in the first direction (the fore-and-aft direction) X. Suchtwo image stabilizer coil portions 18 f and 18 b are collectively calleda first direction actuator. Herein, the image stabilizer coil portion 18f disposed at a front side with respect to the optical axis O is called“a front-side image stabilizer coil portion” while the image stabilizercoil portion 18 b disposed at a back side with respect to the opticalaxis O is called “a back-side image stabilizer coil portion”.

On the other hand, disposed opposite to each other in the seconddirection (the left-and-right direction) Y, the two image stabilizercoil portions 18 l and 18 r are for moving (swinging) the auto-focusinglens holder driving portion (the AF unit) 20 in the second direction(the left-and-right direction) Y. Such two image stabilizer coilportions 18 l and 18 r are collectively called a second directionactuator. Herein, the image stabilizer coil portion 18 l disposed at aleft side with respect to the optical axis O is called “a left-sideimage stabilizer coil portion” while the image stabilizer coil portion18 r disposed at a right side with respect to the optical axis O iscalled “a right-side image stabilizer coil portion”.

As shown in FIG. 4, in the illustrated image stabilizer coil 18, each ofthe front-side image stabilizer coil portion 18 f and the left-sideimage stabilizer coil portion 18 l is divided into two coil parts so asto separate at a center in a longitudinal direction of the front-sidepermanent magnet piece 182 f and the left-side permanent magnet piece182 l opposite thereto, respectively. That is, the front-side imagestabilizer coil portion 18 f comprises a left-side coil part 18 fl and aright-side coil part 18 fr. Likewise, the left-side image stabilizercoil portion 18 l comprises a front-side coil part 18 lf and a back-sidecoil part 18 lb.

In other words, each of the front-side image stabilizer coil portion 18f and the left-side image stabilizer coil portion 18 r comprises twoloop portions while each of the back-side image stabilizer coil portion18 b and the right-side image stabilizer coil portion 18 r comprisesonly one loop portion.

In the manner which is described above, among the four image stabilizercoil portions 18 f, 18 b, 18 l, and 18 r, each of two particular imagestabilizer coil portions 18 f and 18 l disposed in the first direction Xand the second direction Y is divided into the two coil parts 18 fl, 18fr and 18 lf, 18 lb so as to separate it at the center of thelongitudinal direction of the permanent magnet pieces 282 f and 282 lopposite thereto.

The four image stabilizer coil portions 18 f, 18 b, 18 l, and 18 rconfigured as described above in cooperation with the permanent magnet28 are for driving the auto-focusing lens holder driving portion (the AFunit) 20 as a whole in the X-axis direction (the first direction) andthe Y-axis direction (the second direction). A combination of the fourimage stabilizer coil portions 18 f, 18 b, 18 l, and 18 r and thepermanent magnet 28 serves as a voice coil motor (VCM).

In the manner which is described above, the illustrated image stabilizerportion of the lens holder driving device 10 stabilizes the blurryimages by moving the lens barrel received in the auto-focusing lensholder driving portion (the AF unit) 20 in itself in the first direction(the fore-and-aft direction) X and the second direction (theleft-and-right direction) Y. Accordingly, the image stabilizer portionof the lens holder driving device 10 is called an image stabilizerportion of “a barrel shift method”.

Turning back to FIG. 3, the lens holder driving device 10 furthercomprises a shielding cover 42 for covering the auto-focusing lensholder driving portion (the AF unit) 20. The shielding cover 42comprises a rectangular tubular portion 422 for covering an outerperiphery of the auto-focusing lens holder driving portion (the AF unit)20 and a ring-shaped upper end portion 424 for covering an upper surfaceof the auto-focusing lens holder driving portion (the AF unit) 20. Theupper end portion 424 has a circular opening 424 a concentric with theoptical axis O.

The illustrated image stabilizer portion of the lens holder drivingdevice 10 further comprises a position detection arrangement 50 fordetecting a position of the auto-focusing lens holder driving portion(the AF unit) 20 with respect to the base 14 (the fixed portion 13). Theillustrated position detection arrangement 50 comprises a magneticposition detection arrangement comprising two Hall elements 50 f and 50l mounted on the base 14 (see, FIG. 11). The two Hall elements 50 f and50 l are disposed so as to oppose with a space to two of the fourpermanent magnet pieces 282, respectively, in the manner which willlater be described. As shown in FIG. 2, each Hall element 50 f and 50 lis disposed so as to cross in a direction from the north pole to thesouth pole in the permanent magnet piece 282.

In the example being illustrated, one Hall element 50 f is called afront-side Hall element because the Hall element 50 f is disposed at afront side in the first direction (the fore-and-aft direction) X withrespect to the optical axis O. Another Hall element 50 l is called aleft-side Hall element because the Hall element 50 l is disposed at aleft side in the second direction (the left-and-right direction) Y withrespect to the optical axis O.

The front-side Hall element 50 f is disposed on the base 14 at aposition where the front-side image stabilizer coil portion 18 f havingthe divided two coil parts 18 f 1 and 18 fr is separated into the twocoil parts 18 fl and 18 fr. Similarly, the left-side Hall element 50 lis disposed on the base 14 at a position where the left-side imagestabilizer coil portion 18 l having the divided two coil parts 18 lf and18 lb is separated into the two coil parts 18 lf and 18 lb.

In the manner which is described above, the two Hall elements 50 f and50 l are disposed on the base 14 at the positions where particular twoimage stabilizer coil portions 18 f and 18 l having the divided two coilparts 18 fl, 18 fr and 18 lf, 18 lb are separated into two coil parts 18fl, 18 fr and 18 lf, 19 lb.

The front-side Hall element 50 f detects a first position with amovement (a swing) in the first direction (the fore-and-aft direction) Xby detecting a magnetic force of the front-side permanent magnet piece282 f opposite thereto. The left-side Hall element 50 l detects a secondposition with a movement (a swing) in the second direction (theleft-and-right direction) Y by detecting a magnetic force of theleft-side permanent magnet piece 282 l opposite thereto.

Referring to FIGS. 5 through 7, the description will proceed to arelationship between a related magnetic circuit and Hall elements foruse in a related lens holder driving device in order to facilitate theunderstanding of the lens holder driving device 10 according to thefirst exemplary embodiment of the present invention. The relationshipbetween the illustrated related magnetic circuit and the Hall elementsis similar in structure (relationship) to that illustrated in theabove-mentioned Patent Document 17. FIG. 5 is a perspective view showingthe relationship between the related magnetic circuit and the Hallelements, FIG. 6 is a vertical cross sectional view showing therelationship between the related magnetic circuit and the Hall elements,and FIG. 7 is a vertical cross sectional view shoring the relationshipbetween the related magnetic circuit and the Hall elements in a case ofdisplacing the AF unit 20 in the fore-and-aft direction X.

A difference between the related magnetic circuit and the magneticcircuit used in the lens holder driving device 10 according to thisexemplary embodiment is that any of four image stabilizer coil portions18 f′, 18 b′, 18 l′, and 18 r′ constituting an image stabilizer coil 18′in the related magnetic circuit comprises no two loop ports. That is, inthe related magnetic circuit, each of the four image stabilizer coilportions 18 f′, 18 b′, 18 l′, and 18 r′ comprises only one loop part.

As described above, each of the four permanent magnet pieces 282 f, 282b, 282 l, and 282 r has the inner side polarized (magnetized) to thenorth pole and the outer side polarized (magnetized) to the south pole.Arrows B depicted in FIG. 5 indicate directions of magnetic fluxesgenerated by the permanent magnet pieces.

Referring now to FIG. 5, the description will be made as regardsoperation in a case of position adjusting the lens holder 24 (the lensbarrel) in the direction of the optical axis O by using the relatedmagnetic circuit.

By way of illustration, it will be assumed that the AF current is flowedthrough the focusing coil 26 counterclockwise. In this event, accordingto Fleming's right-hand rule, the focusing coil 26 is acted upon by anelectromagnetic force upwards. As a result, it is possible to move thelens holder 24 (the lens barrel) in the direction of the optical axis Oupwards.

Conversely, by flowing the AF current through the focusing coil 26clockwise, it is possible to move the lens holder 24 (the lens barrel)in the direction of the optical axis O downwards.

Referring now to FIGS. 5 to 7, the description will be made as regardsoperation in a case of moving the auto-focusing lens holder drivingportion (the AF unit) 20 as a whole in the first direction (thefore-and-aft direction) X or the second direction (the left-and-rightdirection) Y by using the related magnetic circuit.

First, the description will be made as regards operation in a case ofmoving the auto-focusing lens holder driving portion (the AF unit) 20 asa whole in the first direction (the fore-and-aft direction) X backwards.In this event, as shown in FIG. 5, a first image stabilizing (IS)current flows through the front-side image stabilizer coil portion 18 f′counterclockwise as depicted at an arrow I_(IS1) and a second imagestabilizing (IS) current flows through the back-side image stabilizercoil portion 18 b′ clockwise as depicted at an arrow I_(IS2).

In this event, according to Fleming's right-hand rule, the front-sideimage stabilizer coil portion 18 f′ is acted upon by an electromagneticforce forwards and the back-side image stabilizer coil portion 18 b′ isalso acted upon by an electromagnetic force forwards. However, inasmuchas there image stabilizer coil portions 18 f′ and 18 r′ are fixed to thebase 14 (the fixed portion 13), as reaction, the auto-focusing lensholder driving portion (the AF unit) 20 as a whole is acted upon by anelectromagnetic force backwards, as depicted at arrows F_(IS1) andF_(IS2) in FIG. 6. As a result, it is possible to move the auto-focusinglens holder driving portion (the AF unit) 20 as a whole backwards.

Conversely, by flowing the first IS current through the front-side imagestabilizer coil portion 18 f′ clockwise and by flowing the second IScurrent through the back-side image stabilizer coil portion 18 b′counterclockwise, it is possible to move the auto-focusing lens holderdriving portion (the AF unit) 20 as a whole forwards.

On the other hand, by flowing a third IS current through the left-sideimage stabilizer coil portion 18 l′ counterclockwise and by flowing afourth IS current through the right-side image stabilizer coil portion18 r′ clockwise, it is possible to move the auto-focusing lens holderdriving portion (the AF unit) 20 as a whole rightwards.

In addition, by flowing the third IS current through the left-side imagestabilizer coil portion 18 l′ clockwise and by flowing the fourth IScurrent through the right-side image stabilizer coil portion 18 r′counterclockwise, it is possible to move the auto-focusing lens holderdriving portion (the AF unit) 20 as a whole leftwards.

In the manner which is described above, it is possible to stabilizeblurry images.

Referring now to FIGS. 8 through 10 in addition to FIGS. 5 through 7,the description will proceed to problems in the related lens holderdriving device using the related magnetic circuit in more details.

The description will be made as taking a case as an example where thefirst IS current flows through the front-side image stabilizer coilportion 18 f′ counterclockwise as depicted at the arrow I_(IS1) and thesecond IS current flows through the back-side image stabilizer coilportion 18 b′ clockwise as depicted at the arrow I_(IS2), as shown inFIG. 5, in order to move the auto-focusing lens holder driving portion(the AF unit) 20 as a whole backwards in the manner which is describedabove.

In this event, as shown in FIG. 7, it is understood that a magneticfield B₁₁ produced by the first IS current I_(IS1) flowing through thefront-side image stabilizer coil portion 18 f′ and the magnetic field Bproduced by the front-side permanent magnet piece 282 f are in phase. Itwill be assumed that magnetic flux density of the magnetic field B isindicated by a and magnetic flux density of the magnetic field B₁₁ isindicated by b. Accordingly, it is understood that the front-side Hallelement 50 f detects total magnetic flux density (a+b) obtained bysumming the magnetic flux density a of the magnetic field B and themagnetic flux density b of the magnetic field B₁₁.

It is herein noted that it is necessary that the magnetic flux density aof the magnetic field B and the total magnetic flux density (a+b) are inphase in order to detect a position of the auto-focusing lens holderdriving portion (the AF unit) 20 by means of the front-side Hall element50 f.

FIG. 8 is a view showing a frequency response of the front-side Hallelement 50 f in the related magnetic circuit. In FIG. 8, the horizontalaxis represents a frequency (Frequency) (Hz), the left-hand verticalaxis represents a gain (Gain) (dB), and the right-hand vertical axisrepresents a phase (Phase) (deg). In addition, in FIG. 8, a solid lineindicates a gain characteristic and an alternate long and short dashedline indicate a phase characteristic.

As is apparent from FIG. 8, the frequency response of the font-side Hallelement 50 f is divided into a region I, a region II, and a region III.The region I is a region having a band not higher than a primaryresonance frequency of the actuator and having low frequencies. Theregion II is a region having a band not lower than the primary resonancefrequency of the actuator and having middle frequencies. The region IIIis a region having a band not lower than the primary resonance frequencyof the actuator and having high frequencies.

FIGS. 9A, 9B, and 9C are views showing relationships between phases andmagnitudes among the magnetic flux density a of the magnetic field Bgenerated by the front-side permanent magnetic piece 282 f, the magneticflux density b of the magnetic field B₁₁ generated by the first IScurrent I_(IS1) flowing through the front-side image stabilizer coil 18f′, and the total magnetic flux density (a+b) detected by the front-sideHall element 50 f in the region I, the region II, and the region III ofFIG. 8, respectively. FIG. 10 is a view tabulated for the relationshipsof FIGS. 9A-9C;

It is understood from FIGS. 9A-9C and 10 as follows.

In the band not higher than the primary resonance frequency of theregion I, a magnitude |a| of the magnetic flux density a of the magneticfield B is larger than a magnitude |b| of the magnetic flux density b ofthe magnetic field B₁₁ (|a|>|b|), and the magnetic flux density a of themagnetic field B, the magnetic flux density b of the magnetic field B₁₁,and the total magnetic flux density (a+b) are in phase. Accordingly, inthe region I, it is possible to detect the position of the auto-focusinglens holder driving portion (the AF unit) 20 by means of the front-sideHall element 50 f.

On the other hand, in a band not lower than primary resonance frequency,the magnetic flux density a of the magnetic field B and the magneticflux density b of the magnetic field B₁₁ are opposite phase becausemovement of the front-phase permanent magnet piece 282 f shifts withrespect to a phase of the first IS current I_(IS1) flowing through thefront-side image stabilizer coil portion 18 f′ by 180 degrees.

In the band not lower than the primary resonance frequency of the regionII, the magnetic flux density a of the magnetic field B and the totalmagnetic flux density (a+b) are in phase because the magnitude |a| ofthe magnetic flux density a of the magnetic field B is larger than amagnitude |b| of the magnetic flux density b of the magnetic field B₁₁(|a|>|b|). Accordingly, in the region II, it is possible to detect theposition of the auto-focusing lens holder driving portion (the AF unit)20 by means of the front-side Hall element 50 f.

However, in the band not lower than the primary resonance frequency ofthe region III, it is understood that the magnitude |a| of the magneticflux density a of the magnetic field B is smaller than a magnitude |b|of the magnetic flux density b of the magnetic field B₁₁ (|a|<≡b|).Therefore, the magnetic flux density a of the magnetic field B and thetotal magnetic flux density (a+b) are opposite phase. As a result, inthe region III, it is impossible to detect the position of theauto-focusing lens holder driving portion (the AF unit) 20 by means ofthe front-side Hall element 50 f. That is, an output of Hall element hasresonance.

Accordingly, when the Hall element is disposed between (in) the looppart of the coil, it is understood that it is impossible to detect theposition of the auto-focusing lens holder driving portion (the AF unit)20 in the region III which is not lower than the primary resonancefrequency. In other words, the Hall elements 50 f and 50 l are subjectedto adverse effect caused by the magnetic fields generated by thecurrents flowing through the image stabilizer coil portions 18 f′ and 18l′, respectively.

Referring now to FIGS. 11 through 14, the description will proceed to arelationship between the magnetic circuit according to this exemplaryembodiment and the Hall elements for use in the lens holder drivingdevice 10 according to the first exemplary embodiment of this invention.FIG. 11 is a perspective view showing the relationship between themagnetic circuit according to this exemplary embodiment and the Hallelements, FIG. 12 is a vertical cross sectional view showing therelationship between the magnetic circuit according to this exemplaryembodiment and the Hall elements, FIG. 13 is a vertical cross sectionalview shoring the relationship between the magnetic circuit according tothis exemplary embodiment and the Hall elements in a case of displacingthe AF unit 20 in the fore-and-aft direction X, and FIG. 14 is a crosssectional view taken on line XIV-XIV of FIG. 13.

As described above, each of the four permanent magnet pieces 282 f, 282b, 282 l, and 282 r has the inner side polarized (magnetized) to thenorth pole and the outer side polarized (magnetized) to the south pole.Arrows B depicted in FIG. 11 indicate directions of magnetic fluxesgenerated by the permanent magnet pieces.

Referring now to FIG. 11, the description will be made as regardsoperation in a case of position adjusting the lens holder 24 (the lensbarrel) in the direction of the optical axis O by using the magneticcircuit according to this exemplary embodiment.

By way of illustration, it will be assumed that the AF current is flowedthrough the focusing coil 26 counterclockwise. In this event, accordingto Fleming's right-hand rule, the focusing coil 26 is acted upon by anelectromagnetic force upwards. As a result, it is possible to move thelens holder 24 (the lens barrel) in the direction of the optical axis Oupwards.

Conversely, by flowing the AF current through the focusing coil 26clockwise, it is possible to move the lens holder 24 (the lens barrel)in the direction of the optical axis O downwards.

Referring now to FIGS. 11 to 14, the description will be made as regardsoperation in a case of moving the auto-focusing lens holder drivingportion (the AF unit) 20 as a whole in the first direction (thefore-and-aft direction) X or the second direction (the left-and-rightdirection) Y by using the magnetic circuit according to this exemplaryembodiment.

First, the description will be made as regards operation in a case ofmoving the auto-focusing lens holder driving portion (the AF unit) 20 asa whole in the first direction (the fore-and-aft direction) X backwards.In this event, as shown in FIG. 11, a first image stabilizing (IS)current flows through each of the tow coil parts 18 fl and 18 fr of thefront-side image stabilizer coil portion 18 f counterclockwise asdepicted at an arrow I_(IS1) and a second image stabilizing (IS) currentflows through the back-side image stabilizer coil portion 18 b clockwiseas depicted at an arrow I_(IS2).

In this event, according to Fleming's right-hand rule, the front-sideimage stabilizer coil portion 18 f is acted upon by an electromagneticforce forwards and the back-side image stabilizer coil portion 18 b isalso acted upon by an electromagnetic force forwards. However, inasmuchas there image stabilizer coil portions 18 f and 18 r are fixed to thebase 14 (the fixed portion 13), as reaction, the auto-focusing lensholder driving portion (the AF unit) 20 as a whole is acted upon by anelectromagnetic force backwards, as depicted at arrows F_(IS1) andF_(IS2) in FIG. 12. As a result, it is possible to move theauto-focusing lens holder driving portion (the AF unit) 20 as a wholebackwards.

Conversely, by flowing the first IS current through each of the two coilparts 18 fl and 18 fr of the front-side image stabilizer coil portion 18f clockwise and by flowing the second IS current through the back-sideimage stabilizer coil portion 18 b counterclockwise, it is possible tomove the auto-focusing lens holder driving portion (the AF unit) 20 as awhole forwards.

On the other hand, by flowing a third IS current through each of the twocoil parts 18 lf and 18 lb of the left-side image stabilizer coilportion 18 l counterclockwise and by flowing a fourth IS current throughthe right-side image stabilizer coil portion 18 r clockwise, it ispossible to move the auto-focusing lens holder driving portion (the AFunit) 20 as a whole rightwards.

In addition, by flowing the third IS current through each of the twocoil parts 18 lf and 18 lr of the left-side image stabilizer coilportion 18 l clockwise and by flowing the fourth IS current through theright-side image stabilizer coil portion 18 r counterclockwise, it ispossible to move the auto-focusing lens holder driving portion (the AFunit) 20 as a whole leftwards.

In the manner which is described above, it is possible to stabilizeblurry images in the camera.

Referring now to FIGS. 15 through 17 in addition to FIGS. 11 through 14,the description will proceed to advantages in the lens holder drivingdevice 10 using the magnetic circuit according to this exemplaryembodiment in more details.

The description will be made as taking a case as an example where thefirst IS current flows through each of the two coil parts 18 fl and 18fr of the front-side image stabilizer coil portion 18 f counterclockwiseas depicted at the arrow I_(IS1) and the second IS current flows throughthe back-side image stabilizer coil portion 18 b clockwise as depictedat the arrow I_(IS2), as shown in FIG. 11, in order to move theauto-focusing lens holder driving portion (the AF unit) 20 as a wholebackwards in the manner which is described above.

In this event, as shown in FIGS. 13 and 14, it is understood that amagnetic field B₁₁ produced by the first IS current I_(IS1) flowingthrough the front-side image stabilizer coil portion 18 f and themagnetic field B produced by the front-side permanent magnet piece 282 fare opposite phase. It will be assumed that magnetic flux density of themagnetic field B is indicated by a and magnetic flux density of themagnetic field B₁₁ is indicated by b. Accordingly, it is understood thatthe front-side Hall element 50 f detects total magnetic flux density(a+b) obtained by summing the magnetic flux density a of the magneticfield B and the magnetic flux density b of the magnetic field B₁₁.

It is herein noted that it is necessary that the magnetic flux density aof the magnetic field B and the total magnetic flux density (a+B) are inphase in order to detect a position of the auto-focusing lens holderdriving portion (the AF unit) 20 by means of the front-side Hall element50 f.

FIG. 15 is a view showing a frequency response of the front-side Hallelement 50 f in the magnetic circuit according to this exemplaryembodiment. In FIG. 15, the horizontal axis represents a frequency(Frequency) (Hz), the left-hand vertical axis represents a gain (Gain)(dB), and the right-hand vertical axis represents a phase (Phase) (deg).In addition, in FIG. 15, a solid line indicates a gain characteristicand an alternate long and short dashed line indicate a phasecharacteristic.

As is apparent from FIG. 15, the frequency response of the font-sideHall element 50 f is divided into a region I, a region II, and a regionIII. The region I is a region having a band not higher than a primaryresonance frequency of the actuator and having low frequencies. Theregion II is a region having a band not lower than the primary resonancefrequency of the actuator and having middle frequencies. The region IIIis a region having a band not lower than the primary resonance frequencyof the actuator and having high frequencies.

FIGS. 16A, 16B, and 16C are views showing relationships between phasesand magnitudes among the magnetic flux density a of the magnetic field Bgenerated by the front-side permanent magnetic piece 282 f, the magneticflux density b of the magnetic field B₁₁ generated by the first IScurrent I_(IS1) flowing through the front-side image stabilizer coil 18f, and the total magnetic flux density (a+b) detected by the front-sideHall element 50 f in the region I, the region II, and the region III ofFIG. 15, respectively. FIG. 17 is a view tabulated for the relationshipsof FIGS. 16A-16C;

It is understood from FIGS. 16A-16C and 17 as follows.

In the band not higher than the primary resonance frequency of theregion I, a magnitude |a| of the magnetic flux density a of the magneticfield B is larger than a magnitude |b| of the magnetic flux density b ofthe magnetic field B₁₁ (|a|>|b|), and the magnetic flux density a of themagnetic field B and the total magnetic flux density (a+b) are in phasealthough the magnetic flux density a of the magnetic field B and themagnetic flux density b of the magnetic field B₁₁ are opposite phase.Accordingly, in the region I, it is possible to detect the position ofthe auto-focusing lens holder driving portion (the AF unit) 20 by meansof the front-side Hall element 50 f.

On the other hand, in a band not lower than primary resonance frequency,the magnetic flux density a of the magnetic field B and the magneticflux density b of the magnetic field B₁₁ are in phase because movementof the front-phase permanent magnet piece 282 f is in phase with thefirst IS current I_(IS1) flowing through the front-side image stabilizercoil portion 18 f.

In the band not lower than the primary resonance frequency of the regionII, the magnetic flux density a of the magnetic field B and the totalmagnetic flux density (a+b) are in phase because the magnitude |a| ofthe magnetic flux density a of the magnetic field B is larger than amagnitude |b| of the magnetic flux density b of the magnetic field B₁₁(|a|>|b|). Accordingly, in the region II, it is possible to detect theposition of the auto-focusing lens holder driving portion (the AF unit)20 by means of the front-side Hall element 50 f.

On the other hand, in the band not lower than the primary resonancefrequency of the region III, it is understood that the magnitude lal ofthe magnetic flux density a of the magnetic field B is smaller than amagnitude |b| of the magnetic flux density b of the magnetic field B₁₁(|a|<|b|). However, inasmuch as the magnetic flux density b of themagnetic field B and the magnetic flux density b of the magnetic fieldB₁₁ are in phase, the magnetic flux density a of the magnetic field Band the total magnetic flux density (a+b) are also in phase. As aresult, in also the region III, it is possible to detect the position ofthe auto-focusing lens holder driving portion (the AF unit) 20 by meansof the front-side Hall element 50 f. That is, resonance does not occurin an output of Hall element.

Accordingly, when the Hall element is disposed between the two loopparts of the coil, it is understood that it is possible to detect theposition of the auto-focusing lens holder driving portion (the AF unit)20 in all of frequency ranges. In other words, the Hall elements 50 fand 50 l can avoid to subject to adverse effect caused by the magneticfields generated by the currents flowing through the image stabilizercoil portions 18 f and 18 l, respectively.

FIG. 18 is a cross sectional view showing a relationship of a placementamong one permanent magnet piece 282 of the permanent magnet 28, thefocusing coil 26 disposed around it, and the image stabilizer coilportion 18 in the magnetic circuit illustrated in FIG. 11.

It is understood that a height of the permanent magnet piece 281 ishigher than a height of the focusing coil 26. It is therefore possibleto make a stoke larger in a case of position adjusting the lens holder24 (the lens barrel) in the direction of the optical axis O.

In addition, the permanent magnet piece 282 and the image stabilizercoil portion 18 are disposed so that edges of the permanent magnet piece282 in the radial direction are laid in a coil sectional width of theimage stabilizer coil portion 18 in the radial direction. It istherefore possible to heighten sensitivity of a driving force for movingthe auto-focusing lens holder driving portion (the AF unit) 20 as awhole in a direction orthogonal to the optical axis O.

Incidentally, there is in danger that the four suspension wires 16 maybe fracture in the lens holder driving device 10 having such a structurebecause the four suspension wires 16 are subjected to force in adirection to expand caused by a drop impact or the like. On thisaccount, the lens holder driving device 10 according to this exemplaryembodiment comprises a fracture preventing member for preventing thefour suspension wires 16 from fracturing in the manner which will bepresently described.

Referring to FIGS. 19 and 20, the description will proceed to thefracture preventing member according to this exemplary embodiment indetail. FIG. 19 is a partial perspective view enlargedly showing a partfixing the second end portion 162 of the suspension wire 16 to the upperleaf spring 32, FIG. 20 is a partial cross sectional view of the fixedpart.

In the manner which is described above, the upper leaf spring 32comprises the four arc-shaped extending portions 328 (only onearc-shaped extending portion 328 is shown in FIG. 19) for extending atthe four corners of the upper outer end portion 324 in the radialdirection outwards. The four arc-shaped extending portions 328 have, attip portions thereof, four wire fixing holes 328 a (see, FIG. 3) inwhich the second end portions 162 of the four suspension wires 16 areinserted (fitted), respectively. The second end portions 162 of the foursuspension wires 16 are inserted in the four wire fixing holes 328 a tobe fixed to the four arc-shaped extending portions 328 by means ofsolder 60 or adhesive agent (not shown).

Accordingly, the four arc-shaped extending portions 328 serve as a wirefixing portion for fixing the second end portions 162 of the foursuspension wires 16.

In the lens holder driving device 10 having such a structure, althoughthe auto-focusing lens holder driving portion (the AF unit) 20 issubjected to the force in the direction to apart from the base 14 (thefixed portion 13) due to a drop impact or the like, the auto-focusinglens holder driving portion (the AF unit) 20 moves upward with the fourarc-shaped extending portions 328 elastically deformed in a state wherethe second end portions 162 of the four suspension wire 16 are fixed tothe four arc-shaped extending portions 328.

As a result, it is possible to prevent the four suspension wires 16 fromfracturing. Accordingly, the four arc-shaped extending portions 328 actsas the fracture preventing member for preventing the four suspensionwires 16 from fracturing.

On the other hand, as shown in FIG. 19, the magnet holder 30 comprisesfour upper stoppers 308 (only one upper stopper 308 is shown in FIG. 19)which project at the four corners of the upper ring-shaped end portion304 upwards. Each upper stopper 308 projects from an opening 32 a formedin the upper leaf spring 32 between the upper outer end portion 324 andthe each arc-shaped extending portion 328.

In other words, the four upper stoppers 308 project from the magnetholder 30 toward an inner wall surface of the shielding cover 42.

By the four upper stoppers 308, movement of the auto-focusing lensholder driving portion (the AF unit) 20 upwards is limited. In otherwords, when auto-focusing lens holder driving portion (the AF unit) 20moves upwards, the four upper stoppers 308 of the magnet holder 30 hitsto the inner wall surface of the upper end portion 424 of the shieldingcover 42 although the four arc-shaped extending portions 328 becomeelastically deformed before the four arc-shaped extending portions 328buckle or before the four suspension wires 16 are subjected to afracturing force.

That is, the four upper stoppers 308 serve as a fracture preventionsupporting member for supporting prevention of fracture in the foursuspension wires 16.

As shown in FIG. 2, there is little clearance (gap) between the fixedportion 13 (the coil board 40) and the auto-focusing lens holder drivingportion (the AF unit) 20. Accordingly, although the auto-focusing lensholder driving portion (the AF unit) 20 is subjected to a force in adirection to get near the fixed portion 13 (the coil board 40) due to adrop impact or the like, the four suspension wires 16 do not bucklebecause the auto-focusing lens holder driving portion (the AF unit) 20immediately hits to an upper surface of the fixed portion 13 (the coilboard 40).

Referring to FIG. 21 in addition to FIGS. 2 to 4, the description willproceed to the flexible printed circuit (FPC) 44 disposed between thebase 41 and the coil board 40 and a method of mounting it. FIG. 21 is aperspective view showing an assembly of the coil board 40 and theflexible printed circuit (FPC) 44 seen from a rear side;

As shown in FIG. 3, the base 14 has four positioning protrusions 142which project upwards on diagonal lines in vicinity of the circularopening 14 a in the radial direction outwards. On the other hand, asshown in FIG. 4, the coil board 40 has four positioning hole portions 40b in which the four positioning protrusions 142 are charged,respectively. As shown in FIG. 21, the flexible printed circuit (FPC) 44also has four positioning hole portions 44 a at positions correspondingto the four positioning hole portions 40 b. Accordingly, the fourpositioning protrusions 142 of the base 14 are charged in the fourpositioning hole portions 40 b of the coil board 40 via the fourpositioning hole portions 44 a of the flexible printed circuit (FPC) 44.

As shown in FIG. 21, the flexible printed circuit (FPC) 44 has a rearsurface on which the two Hall elements 50 f and 50 l are mounted. On theother hand, as shown in FIG. 2, the base 14 has concave portions 14 b inwhich the two Hall elements 50 f and 50 l are fitted.

As shown in FIG. 4, on the coil board 40, six lands 18 a for supplyingelectric currents to the four image stabilizer coil portions 18 f, 18 b,18 l, and 18 r are formed along the circular opening 40 a bored at acentral portion thereof. On the other hand, as shown in FIG. 21, on theflexible printed circuit (FPC) 44, six notch portions 44 b are formed atpositions corresponding to the six lands 18 a. Accordingly, by mountingsolder pastes on the six notch portions 44 b and by carrying out solderreflow, it is possible to electrically connect internal wiring (notshown) of the flexible printed circuit (FPC) 44 with the six lands 18 aof the coil board 44.

In the manner which is described above, the first end portions 161 ofthe four suspension wires 16 pass through the four through holes 40 a ofthe coil board 40 and are fixed to the coil board 40.

As shown in FIG. 4, on the coil board 40, four lands are formed aroundthe four through holes 40 a, respectively. Among the four lands formedaround the through holes 40 a, two lands (right-back and left-front inthe example of FIG. 4) are electrically connected to the inner wiring(not shown) of the flexible printed circuit (FPC) 44 by means of solder.Accordingly, among the four suspension wires 16, the first end portions161 of the two suspension wires 16 are fixed to the coil board 40 at theabove-mentioned two lands by means of the above-mentioned solder and areelectrically connected to the flexible printed circuit (FPC) 44. On theother hand, the first end portions 161 of remaining two suspension wires16 are fixed to the coil board 40 at remaining two lands by means ofsolder or adhesive agent but are electrically insulated to the internalwiring (not shown) of the flexible printed circuit (FPC) 44.

As shown in FIG. 21, the flexible printed circuit (FPC) 44 has a rearsurface on which a control portion 46 is mounted. The control portion 46controls the AF current flowing through the focusing coil 16 andcontrols the first through fourth IS currents flowing through the fourimage stabilizer coil portions 18 f, 18 b, 18 l, and 18 r so as tocompensate wobbling detected based on two directional gyro sensors (notshown) on the basis of position detected signals detected by the twoHall elements 50 f and 50 l.

Referring to FIGS. 22 and 23, the description will proceed to a methodfor feeding to the focusing coil 26. FIG. 22 is a plan view showing astate where the shielding cover 42 is omitted from the lens holderdriving device 10. FIG. 23 is a partial enlarged perspective viewenlargedly showing a tied-up part of an end portion of a wire composedof the focusing coil 26.

As shown in FIG. 22, lens holder 24 has, at an upper end thereof, firstand second projecting portions 241 and 242 which project in a direction(outwards in the radial direction) to apart from each other in theleft-and-right direction Y. In the example being illustrated, the firstprojecting portion 241 is also called a right-side projecting portionbecause it projects to right side while the second projecting portion242 is also called a left-side projecting portion because it projects toleft side.

On the other hand, the wire composed of the focusing coil 26 has firstand second end portions 261 and 262. As shown in FIG. 23, the first endportion 261 of the wire of the focusing coil 26 is tied up to the firstprojecting portion (the right-side projecting portion) 241 of the lensholder 24. Similarly, the second end portion 262 of the wire of thefocusing coil 26 is tied up to the second projecting portion (theleft-side projecting portion) 242 of the lens holder 24. Accordingly,the first and second end portions 261 and 262 are also called first andsecond tied-up parts, respectively.

On the other hand, as shown in FIG. 22, the first leaf spring (the upperleaf spring) 32 comprises first and second leaf spring pieces 32-1 and32-2 which are electrically insulated from each other. The first andsecond leaf spring pieces 32-1 and 32-2 have rotational symmetry shapeswith respect to the optical axis O of the lens as a center. The firstleaf spring piece 32-1 is disposed, at the first end (the upper end) ofthe magnet holder 30, substantially back side and right side while thesecond leaf spring piece 32-2 is disposed, at the first end (the upperend) of the magnet holder 30, substantially front side and left side.

The upper inner end portion 322 of the first leaf spring piece 32-1disposed at the right side has a first U-shaped terminal portion 322-1projecting rightwards (outwards in the radial direction) at a positioncorresponding to the first projecting portion (the right-side projectingportion) 241 of the lens holder 24. Likewise, the upper inner endportion 322 of the second leaf spring piece 32-2 disposed at theleft-side has a second U-shaped terminal portion 322-2 projectingleftwards (outwards in the radial direction) at a position correspondingto the second projecting portion (the left-side projecting portion) 242of the lens holder 24. The first U-shaped terminal portion 322-1 is alsocalled a right-side U-shaped terminal portion while the second U-shapedterminal portion 322-2 is also called a left-side U-shaped terminalportion.

The first U-shaped terminal portion (the right-side U-shaped terminalportion) 322-1 is electrically connected to the first end portion (thefirst tied-up part) 261 of the focusing coil 26 by means of solder (notshown) at the first projecting portion (the right-side projectingportion) 241 of the lens holder 24. Similarly, the second U-shapedterminal portion (the left-side U-shaped terminal portion) 322-2 iselectrically connected to the second end portion (the second tied-uppart) 262 of the focusing coil 26 by means of solder (not shown) at thesecond projecting portion (the left-side projecting portion) 242 of thelens holder 24.

In addition, in the manner which is described above, among the foursuspension wires 16, the second end portions 162 of the two suspensionwires 16 (right-back and left-front in the example of FIG. 22) areconnected to the arc-shaped extending portions 328 through the wirefixing holes 328 a by means of solder 60. The second end portions 162 ofremaining two suspension wires 16 (left-back and right-front in theexample of FIG. 22) are fixed to the arc-shaped extending portions 328through the wire fixing holes 328 a by means of adhesive agent 62.Solder may be used in lieu of the adhesive agent 62.

Furthermore, in the manner which is described above, among the foursuspension wires 16, the first end portions 161 of the two suspensionwires 16 (right-back and left-front in the example of FIG. 22) are fixedto the lands of the coil board 44 via the through holes 40 a by means ofsolder and are electrically connected to the flexible printed circuit(FPC) 44. The first end portions 161 of the remaining two suspensionwires 16 (left-back and right-front in the example of FIG. 22) areconnected to the lands of the coil board 40 via the through holes 40 aby means of solder or adhesive agent but are electrically insulated fromthe flexible printed circuit (FPC) 44.

Accordingly, the flexible printed circuit (FPC) 44 is electricallyconnected to the first end portion (the first tied-up part) 261 of thefocusing coil 26 via the suspension wire 16 of the right-back, the firstleaf spring piece 32-1 of the first leaf spring (the upper leaf spring)32, and the first U-shaped terminal portion (the right-side U-shapedterminal portion) 322-1. Similarly, the flexible printed circuit (FPC)44 is electrically connected to the second end portion (the secondtied-up part) 262 of the focusing coil 26 via the suspension wire 16 ofthe left-front, the second leaf spring piece 32-2 of the first leafspring (the upper leaf spring) 32, and the second U-shaped terminalportion (the left-side U-shaped terminal portion) 322-2.

In the manner which is described above, feeding to the focusing coil 26is carried out from the flexible printed circuit (FPC) 44 via the twosuspension wires 16 and the first leaf spring 32.

New, the description will proceed to a method of assembling the lensholder driving device 10.

First, the auto-focusing lens holder driving portion (the AF unit) 20 ismanufactured by assembling the lens holder 24, the focusing coil 26, thepermanent magnet 28, the magnet holder 30, the upper leaf spring 32, thelower leaf spring 34, and the spacer 36.

On the other hand, an assembly consisting of the coil board 40 and theflexible printed circuit (FPC) 44, as shown in FIG. 21, is manufacturedby the above-mentioned solder reflow. The assembly is mounted on thebase 14 provided the side of the first terminal portions 161 of the foursuspension wires 16.

Subsequently, the above-mentioned auto-focusing lens holder drivingportion (the AF unit) 20 is mounted on the base 14 via theabove-mentioned assembly and the second end portions 162 of the foursuspension wires 14 are fixed to the arc-shaped extending portions 328via the wire fixing holes 328 a by means of the solder 60 or theadhesive agent 62.

The first and second U-shaped terminal portions 322-1 and 322-2 of thefirst leaf spring (the upper leaf spring) 32 are connected to the firstand second end portions 261 and 261 of the focusing coil 26.

Lastly, the shielding cover 42 is put so as to cover the auto-focusinglens holder driving portion (the AF unit) 20 and a lower end of theshielding cover 42 is fixed to the base 14.

As such a manner, it is possible to easily assemble the lens holderdriving device 10.

The lens holder driving device 10 assembled in such a manner has a sizeof 11 mm×11 mm×4.2 mm.

The above-mentioned lens holder driving device 10 according to the firstexemplary embodiment of the present invention has effects which will bepresently described.

First, it is possible for the two Hall elements 50 f and 50 l to avoid adetrimental effect caused by the magnetic field generated by the currentflowing through the specific two image stabilizer coil portions 18 f and18 l because the two Hall elements 50 f and 50 l are disposed on thebase 14 at the positions where the specific two image stabilizer coilportions 18 f and 18 l are separated into the respective two coil parts18 f 1, 18 fr and 18 lf, 18 lb.

Secondly, it is possible to prevent the four suspension wires 15 fromfracturing and to heighten impact resistance of the lens holder drivingdevice 10 because the lens holder driving device comprises the fracturepreventing member 328.

Thirdly, it is possible to electrically connect the inner wiring of theflexible printed circuit (FPC) 44 with the plurality of lands 18 a ofthe coil board 40 by means of solder reflow because the notch portions44 b are formed to the flexible printed circuit (FPC) 44 at thepositions corresponding to the plurality of lands 18 a formed on thecoil board 40.

Fourthly, it is possible to make the stoke in the case of positionadjusting the lens holder 24 (the lens barrel) in the direction of theoptical axis O larger because the height of the focusing coil 26 islower than the height of the permanent magnet piece 282.

Fifthly, it is possible to enhance sensitivity of the driving force formoving the auto-focusing lens holder driving portion (the AF unit) 20 asa whole in the direction orthogonal to the optical axis O because thepermanent magnet pieces 282 and the image stabilizer coil portions 18are disposed so that the edges of the permanent magnet pieces in theradial direction are laid in the coil sectional width of the imagestabilizer coil portions 18 in the radial direction.

Referring to FIGS. 24 and 25, the description will proceed to a lensholder driving device 10A according to a second exemplary embodiment ofthe present invention. FIG. 24 is a vertical cross sectional view of thelens holder driving device 10A. FIG. 25 is an exploded perspective viewof the lens holder driving device 10A.

Herein, in the manner shown in FIGS. 24 and 25, an orthogonal coordinatesystem (X, Y, Z) is used. In a state illustrated in FIGS. 24 and 25, inthe orthogonal coordinate system (X, Y, X), an X-axis direction is afore-and-aft direction (a depth direction), a Y-axis direction is aleft-and-right direction (a width direction), and a Z-axis direction isan up-and-down direction (a height direction). In addition, in theexample being illustrated in FIGS. 24 and 25, the up-and-down directionZ is a direction of an optical axis O of a lens. In the second exemplaryembodiment, the X-axis direction (the fore-and-aft direction) is calleda first direction while the Y-axis direction (the left-and-rightdirection) is called in a second direction.

However, in an actual use situation, the direction of the optical axisO, namely, the Z-axis direction becomes a fore-and-aft direction. Inother words, an upper direction of the Z-axis becomes a front directionwhile a lower direction of the Z-axis becomes a rear direction.

The illustrated lens holder driving device 10A includes an auto-focusinglens holder driving portion 20A and an image stabilizer portion forstabilizing blurry images produced in the auto-focusing lens holderdriving portion 20A on picking up a static image using a miniaturecamera for a mobile terminal and is a device which can pick up the imagefree from image blurred.

The illustrated lens holder driving device 10A has a structure in whichthe lens holder driving device 10 according to the above-mentioned firstexemplary embodiment is substantially turned upside down. Accordingly,it is suitable to change “upper” into “lower” and to change “lower” into“upper”. In order to simplify the description, the same reference signsare attached to those having functions similar those of the lens holderdriving device 10 according to the first exemplary embodiment and thedescription will later be made as regards only differences.

A lend barrel 12 has a shape like a hanging bell. In place of theshielding cover 42, a shielding wall 422A having a rectangular tubularshape and a second base (a cover) 424A are used. In the auto-focusinglens holder driving portion (an AF unit) 20A, a spacer 36A is mounted tothe lower leaf spring 32 serving as a first leaf spring.

A configuration except for those is similar to the above-mentioned lensholder driving device 10 according to the first exemplary embodiment.

Accordingly, the lens holder driving device 10A according to the secondexemplary embodiment of the present invention has effects similar tothose of the above-mentioned lens holder driving device 10 according tothe first exemplary embodiment.

While this invention has been particularly shown and described withreference to the exemplary embodiments thereof, the invention is notlimited to the embodiment. It will be understood by those of ordinaryskill in the art that various changes in form and details may be thereinwithout departing from the spirit and scope of the present invention asdefined by the claims.

For example, although the plurality of suspension wires having the firstend portions fixed to the periphery of the fixed portion are used as thesupporting member for swingably supporting the auto-focusing lens holderdriving portion with respect to the fixed portion, the supporting memberis not limited to those.

The whole or part of the exemplary embodiments disclosed above can bedescribed as, but not limited to, the following supplementary notes.

(Supplementary Note 1)

A lens holder driving device (10; 10A) comprising:

an auto-focusing lens holder driving portion (20; 20A) moving a lensholder (24) holding a lens barrel (12) along an optical axis (O); and

an image stabilizer portion stabilizing image blurred by moving saidauto-focusing lens holder driving portion (20; 20A) in first and seconddirections (X, Y) which are orthogonal to the optical axis (O) and whichare perpendicular to each other,

wherein said auto-focusing lens holder driving portion (20; 20A)comprises:

a focusing coil (26) fixed to said lens holder (24);

a permanent magnet (28) comprising a plurality of permanent magnetpieces (282 f, 282 b, 282 l, 282 r) which have first surfaces opposed tosaid focusing coil (26) and which are disposed outsides of said focusingcoil (26) with respect to the optical axis (O) in a radial direction soas to oppose to each other in the first direction (X) and the seconddirection (Y);

a magnet holder (30), disposed around the periphery of said lens holder(24), holding said permanent magnet (28), said magnet holder (30) havingfirst and second ends (30 a, 30 b) opposite to each other in a directionof the optical axis (O); and

first and second leaf springs (32, 34), mounted to the first and thesecond ends (30 a, 30 b) of said magnet holder (30), supporting saidlens holder (24) in the direction of the optical axis (O) shiftably soas to position said lens holder (24) in the radial direction,

wherein said image stabilizer portion comprises:

a fixed portion (13) disposed apart from said auto-focusing lens holderdriving portion (20; 20A) in the direction of the optical axis (O) at aposition in the vicinity of said second leaf spring (34);

a supporting member (16) swingably supporting said auto-focusing lensholder driving portion (20; 20A) in the first direction (X) and thesecond direction (Y) with respect to said fixed portion (13);

an image stabilizer coil (18) comprising a plurality of image stabilizercoil portions (18 f, 18 b, 18 l, 18 r) mounted on said fixed portion(13) so as to oppose to second surfaces of said plurality of pluralityof permanent magnet pieces (282 f, 282 b, 282 l, 282 r) that areperpendicular of to the first surfaces, said image stabilizer coil (18)comprising specific image stabilizer coil portions (18 f, 18 l), amongsaid plurality of hand blurring correction coil portions, disposed inthe first direction (X) and the second direction (Y), each of saidspecific image stabilizer coil portions (18 f, 18 l) being divided intoa plurality of coil parts (18 fl, 18 fr; 18 lf, 18 lb) so as to separatein a longitudinal direction of said permanent magnet piece (282 f, 282l) opposed thereto; and

a plurality of Hall elements (50 f, 50 l) disposed on said fixed portion(13) at positions where each of said specific image stabilizer coilportions (18 f, 18 l) are separated into said plurality of coil portions(18 fl, 18 fr; 18 lf, 18 lb).

(Supplementary Note 2)

The lens holder driving device according to Supplementary note 1,wherein said permanent magnet (28) comprises four permanent magnetpieces (282 f, 282 b, 282 l, 282 r),

wherein said image stabilizer coil (18) comprises four image stabilizercoil portions (18 f, 18 b, 18 l, 18 r) including two specific imagestabilizer coil portions (18 f, 18 l) disposed in the first direction(X) and the second direction (Y), each of said two specific imagestabilizer coil portions (18 f, 18 l) being divided into two coil ports(18 fl, 18 fr; 18 lf, 18 lb) so as to separate at a center in thelongitudinal direction of the permanent magnet piece (282 f, 282 l)opposed thereto,

wherein said plurality of Hall elements comprise two Hall elements (50f, 50 l), said two Hall elements (50 f, 50 l) being disposed on saidfixed portion (13) at the positions where each of said two specificimage stabilizer coil portions (18 f, 18 l) are separated into said twocoil parts (18 fl, 18 fr; 18 lf, 18 lb).

(Supplementary Note 3)

The lens holder driving device according to Supplementary note 1,wherein said supporting member comprises a plurality of suspension wires(16) having first end portions (161) fixed to said fixed portion (13) atouter regions thereof, said plurality of suspension wires (16) extendingalong the optical axis (O) and swingably supporting said auto-focusinglens holder driving portion (20; 20A) in the first direction (X) and thesecond direction (Y).

(Supplementary Note 4)

The lens holder driving device according to Supplementary note 3,wherein the plurality of suspension wires (16) have second end portions(162) fixed to said first leaf spring (32).

(Supplementary Note 5)

The lens holder driving device according to Supplementary note 4,wherein said lens holder (24) comprises a tubular portion (240) holdingsaid lens barrel (12) and protrusion portions (241, 242) projecting froman outer wall of said tubular portion (240),

wherein said focusing coil (26) is made of a wire having end portions(261, 262) which are tied up to said protrusion portions,

wherein said first leaf spring (32) has terminal portions (322-1, 322-2)projecting therefrom so as to be disposed in the vicinity of saidprotrusion portions,

wherein said terminal portions (322-1, 322-2) and the end portions (261,262) of said wire tied up to said protrusion portions (241, 242) areelectrically connected, whereby feeding from said suspension wires (16)to said focusing coil (26) through said first leaf spring (32).

In this connection, inasmuch as reference symbols in parentheses areattached in order to facilitate an understanding of this invention andare merely one example thereof, this invention is, of course, notlimited to them.

What is claimed is:
 1. A lens holder driving device comprising: anauto-focusing lens holder driving portion moving a lens holder holding alens barrel along an optical axis; and an image stabilizer portionstabilizing image blur by moving said auto-focusing lens holder drivingportion in first and second directions which are orthogonal to theoptical axis and which are perpendicular to each other, wherein saidauto-focusing lens holder driving portion comprises: a focusing coilfixed to said lens holder; a permanent magnet comprising a plurality ofpermanent magnet pieces which have first surfaces opposed to saidfocusing coil and which are disposed outsides of said focusing coil withrespect to the optical axis in a radial direction so as to oppose toeach other in the first direction and the second direction; a magnetholder, disposed around the periphery of said lens holder, holding saidpermanent magnet, said magnet holder having first and second endsopposite to each other in a direction of the optical axis; and first andsecond leaf springs, mounted to the first and the second ends of saidmagnet holder, supporting said lens holder in the direction of theoptical axis shiftably so as to position said lens holder in the radialdirection, wherein said image stabilizer portion comprises: a fixedportion disposed apart from said auto-focusing lens holder drivingportion in the direction of the optical axis at a position in thevicinity of said second leaf spring; a supporting member swingablysupporting said auto-focusing lens holder driving portion in the firstdirection and the second direction with respect to said fixed portion;an image stabilizer coil comprising a plurality of image stabilizer coilportions mounted on said fixed portion so as to oppose second surfacesof said plurality of permanent magnet pieces that are perpendicular ofto the first surfaces, said image stabilizer coil comprising specificimage stabilizer coil portions, among said plurality of image stabilizercoil portions, disposed in the first direction and the second direction,each of said specific image stabilizer coil portions being divided intoa plurality of coil parts so as to separate in a longitudinal directionof said permanent magnet piece opposed thereto; and a plurality of Hallelements disposed on said fixed portion at positions where each of saidspecific image stabilizer coil portions are separated into saidplurality of coil portions.
 2. The lens holder driving device as claimedin claim 1, wherein said permanent magnet comprises four permanentmagnet pieces, wherein said image stabilizer coil comprises four imagestabilizer coil portions including two specific image stabilizer coilportions disposed in the first direction and the second direction, eachof said two specific image stabilizer coil portions being divided intotwo coil ports so as to separate at a center in the longitudinaldirection of the permanent magnet piece opposed thereto, wherein saidplurality of Hall elements comprise two Hall elements, said two Hallelements being disposed on said fixed portion at the positions whereeach of said two specific image stabilizer coil portions are separatedinto said two coil parts.
 3. The lens holder driving device as claimedin claim 1, wherein said supporting member comprises a plurality ofsuspension wires having first end portions fixed to said fixed portionat outer regions thereof, said plurality of suspension wires extendingalong the optical axis and swingably supporting said auto-focusing lensholder driving portion in the first direction and the second direction.4. The lens holder driving device as claimed in claim 3, wherein theplurality of suspension wires have second end portions fixed to saidfirst leaf spring.
 5. The lens holder driving device as claimed in claim4, wherein said lens holder comprises a tubular portion holding saidlens barrel and protrusion portions projecting from an outer wall ofsaid tubular portion, wherein said focusing coil is made of a wirehaving end portions which are tied up to said protrusion portions,wherein said first leaf spring has terminal portions projectingtherefrom so as to be disposed in the vicinity of said protrusionportions, wherein said terminal portions and the end portions of saidwire tied up to said protrusion portions are electrically connected,whereby feeding from said suspension wires to said focusing coil throughsaid first leaf spring.